Transcranial segment of the trigeminal nerve: Macro-/microscopic anatomical study using sheet plastination

摘要

Background: Trigeminal neuralgia (TN) may be caused by the mechanical compression of the trigeminal nerve. In the studies on the location of mechanical irritation and entrapment of the nerve, attention has been paid mostly to vascular structures in the subarachnoid space. Few studies have explored the relationship between the trigeminal nerve and its surrounding structures along its course in the skull base. The aim of this study was to examine and trace the root, ganglion and three divisions of the trigeminal nerve and their relationships with surrounding soft and bony structures in the skull base, and to identify the likely mechanical compression points. Methods: A total of 26 adult cadavers (ten females, 16 males; age range, 45-81 years) were examined in this study, eight for dissection and 16 for sheet plastination study. Results: Anatomical structures that may make the trigeminal nerve susceptible to entrapment in the skull base were located at (1) the inferolateral edge of the mouth of Meckel's cave, (2) the middle cranial fossa dura and the lateral wall of the anterior intracavernous portion of the internal carotid artery, (3) the ridge of the medial wall of the foramen rotundum, and (4) the twisted periosteum and venous plexus of the foramen ovale. Conclusion: This study identified four likely mechanical compression points along the course of the trigeminal nerve in the skull base. Knowledge of these TN-susceptible sites may be useful to both skull base surgeon and TN-animal model researcher, particularly when they study TN without vascular compression.